Transparent Wrapping Paper

ABSTRACT

A transparent wrapping paper with high freeness, which exhibits a zigzag embossing in a plan view on the paper surface, as well as a procedure for the production of the same are described.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to German patent application Serial No. 102006044524.4, filed Sep. 21, 2006, entitled “Transparent Wrapping Paper,” under 35 U.S.C. 119(a).

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to the field of transparent wrapping paper having a zigzag embossing and procedures for production of the same.

2. Description of Related Art

Transparent tracing paper is used today particularly as printing carrier for high-quality printings or as technical drawing paper in engineering and architecture fields. A use of transparent paper as high-quality packing material is not yet known. For this use as a packing material one needs a high-weighty (basis weights lie in a range from 250 to 500 g/m²) and cardboard-like product with the necessary rigidity. Transparent paper usually becomes largely opaque and inflexible within the higher basis weight range and is difficult to process. These disadvantages are due to the physical condition of transparent paper.

Furthermore, transparent paper can be bent or folded with higher basis weight (250 to 500 g/m²) only with difficulty, and is inclined to breaking open along any folded lines.

A further disadvantage of high-weighty transparent paper consists of the fact that with high basis weights of over 150 g/m² transparency is lost. Thus, the otherwise “milkily”-translucent product works with basis weights of over 150 g/m² very jerkily and cloudily.

A need exists for a transparent wrapping paper, which is not afflicted with the disadvantages described above, as well as a making a procedure available for the production of the same.

The present invention provides a solution to these needs and other problems, and offers other advantages over the prior art.

BRIEF SUMMARY OF THE INVENTION

The present invention provides a transparent wrapping paper. The present invention furthermore provides a process for producing a transparent wrapping paper.

A further embodiment of the present invention is an envelope material, which consists of a wrapping paper.

The present invention is related to a material that solves the above-mentioned problems. In accordance with one embodiment of the invention, a transparent wrapping paper with zigzag embossing as well as a procedure for the production of the same is described. In particular, a preferred embodiment envelope material utilizing wrapping paper with zigzag embossing is described.

Additional advantages and features of the invention will be set forth in part in the description which follows, and in part, will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a side view of wrapping paper in cutting plane in longitudinal direction of the paper in accordance with one aspect of the invention.

FIG. 2 illustrates a plan view on the paper surface of an embodiment of the wrapping paper in accordance with one aspect of this invention.

FIG. 3 is a perspective plan view on the paper surface of the wrapping paper in accordance with one aspect of this invention.

FIGS. 4 and 5 is a top view of an envelope material formed from wrapping paper in accordance with one aspect of this invention.

Throughout the drawings, the same reference numerals indicate similar or corresponding features or functions.

DETAILED DESCRIPTION

A relatively easy and low-weighty transparent paper which receives its rigidity by embossing is described below in accordance with a preferred embodiment of the invention. The transparent wrapping paper is a transparent paper with a high freeness. The freeness typically is over 60, preferably over 80, and in particular is over 90 degrees Schopper Riegler. Degrees Schopper Riegler (° SR) is a term used to describe slowness of how slowly water is drained from paper pulp. An alternative and opposite measure is freeness of how quickly water is drained from paper pulp that may be reported as ml Canadian Standard Freeness (CSF). Freeness or slowness is the function of beating or refining. More specifically, the Schopper-Riegler (SR) provides a measure of the rate at which a dilute suspension of pulp may be dewatered. It has been shown that the drainability is related to the surface conditions and swelling of the fibres, and constitutes a useful index of the amount of mechanical treatment to which the pulp has been subjected.

In accordance with an embodiment of the present invention as described herein transparent paper differs from greaseproof paper, glassine weighing paper, and/or parchment or wax paper. The freeness of these other paper products lies much lower (usually with 30-40° SR). Transparent paper has thereby also an unmistakable appearance. It is more transparent than greaseproof paper.

Transparent paper usually consists of cellulose fibers from sources such as flax, rags, or hardwood. Preferably, the transparent paper consists of long-fibrous cellulose, which is solubilized in the sulfate process.

In order to change the characteristics of the transparent paper, if desired, different mixtures of different cellulose fibers can be used. The basis weight of the transparent wrapping paper according to a preferred embodiment of the invention usually amounts to 40 to 200 g/m², preferably 60 to 180 g/m², in particular 80 to 150 g/m². The transparent paper receives its transparent character by strong grinding of the cellulose fibers. Thus, numerous hydrogen bonds in the paper structure, which produce a very firm and hard structure of the final product, develop. In order to achieve a sufficient rigidity, the transparent paper is subjected to an embossing treatment. The embossing must reinforce the transparent paper in sufficient way in a longitudinal direction and in a transverse direction. Furthermore, the embossing must produce a profile, which ensures that the product is suitable for machine processing (e.g., processing with grooves and stamping machines). In addition, ideally the paper in longitudinal direction does not stretch too much during tensile stress.

In FIGS. 1 and 2, an example of the transparent paper 100 in accordance with one embodiment of the present invention which maintains an embossing is shown. This paper 100 shows in FIG. 2 a preferably continuous zigzag form 102 on the surface when viewed in a plan view of the wrapping paper.

When viewed in the cutting plane or cross section or side view of the transparent paper 100, as shown in FIG. 1, in longitudinal direction the corrugation 104 of the paper 100 is wavy. In the cardboard industry, cross section views of wavy profiles are well-known; however, these profiles are linear (not zigzag) in the plan view. Also, cardboard always has the outside parts of the wave profile covered. In the transparent paper 100, according to a preferred embodiment of the invention, though no lamination is done. Rather according to a preferred embodiment of the invention, transparent paper having a high freeness is very rigid and “cardboard like” by its high density and firmness and without using lamination.

The transparent paper is usually embossed according to a preferred embodiment of the invention with a zigzag grooved roller. The embossing can be applied full-laminar, part-laminar or partially—by grooved rollers or other such things—on the transparent paper. The embossing rollers exhibit the desired embossing shape, and the transparent paper is processed between the embossing roll as well as a counter-pressure roller. The image of the roller embossing will transfer to the transparent paper.

Under embossed one understands according to the invention that the transparent paper permanently maintains the embossed sample for the site conditions. Such site conditions that do not affect the transparent paper during application include air humidity and temperature. Preferably the embossed sample remains stable at temperatures of up to approximately 40° C., more preferentially to approximately 60° C. and a relative air humidity of up to 90%, more preferentially up to about 80% relative air humidity. An embossed sample is regarded within the range of the invention as stable, if up to a temperature and a relative air humidity indicated above no visually observable change occurs of the depth or sharpness of the embossed sample without intervention from other forces.

As shown in FIG. 3, the embossing height 116 from apex 112 to apex 114 with view in cutting plane of the transparent paper 100 in longitudinal direction (=distance of the parallel zigzag embossings) is usually with less than 2 mm, preferably less than about 1 mm, and in particular with less than 0.8 mm; however usually with at least 0.1 mm, preferably with at least 0.2 mm. The distance 110 of the zigzag lines 102 to each other from vertex 106 to vertex 108 lies usually likewise with less than 2 mm, preferably less than 1 mm, and in particular with less than 0.8 mm.

Typically, the embossing of special papers takes place in a sinusoidal wave, which runs in straight lines, if one regards the product in plan view on the surface. The embossing form is according to a preferred embodiment of the invention against it a zigzag line 102 with straight connecting distances between the apexes (see FIG. 2 and FIG. 3). The width 118 of the linear distances usually amounts to 0.5 to 2.0 cm, and preferably 1.0 to 1.5 cm. In an optional execution form the zigzag line can be interrupted with view in plan view on the paper surface by several longitudinal bars (not shown). In a further optional execution form the zigzag line can be interrupted with view in plan view on the paper surface by one or more transverse bars. In a further optional execution form the zigzag line can be interrupted with view in plan view on the paper surface by one or more longitudinal and transverse bars. The length of the longitudinal and transverse bars amounts to usually 2 to 10 mm, preferably 4 to 8 mm, and in particular 6 mm. The width of the longitudinal and transverse bars amounts to usually 1 to 4 mm, preferably 1.5 to 3 mm, in particular 2 mm. The height of the longitudinal and transverse bars from apex to apex amounts to usually 0.5 to 2 mm, preferably 0.8 to 1.4 mm, and in particular 1 mm. This brings the advantage to the product of a higher reinforcement.

The embossed transparent wrapping paper differs thus from cardboard in such a way that the wrapping paper according to the invention consists only of the embossed transparent paper and the transparent wrapping paper undersurface is not covered up (with a “liner”). The embossed transparent wrapping paper may be used for example as a packing material, a covering material for mailings, like envelopes, packages and packets, a wrapping material, and used for other purposes.

One example use is as an envelope material 150 as shown in FIGS. 4 and 5, which consists of a transparent wrapping paper with high freeness, which exhibits a zigzag embossing in a plan view on the paper surface. This envelope material can be manufactured for example by a procedure with which a transparent paper 100 with high freeness is folded into an envelope material 150, and then on which a zigzag profile is embossed into this folded transparent paper 100 with high freeness. This envelope material 150 alternatively can be manufactured by a procedure with which a zigzag profile is embossed into a transparent paper 100 with high freeness, and then the embossed transparent paper 100 is folded to an envelope material 150.

The foregoing merely illustrates the principles of the invention. It will thus be appreciated that those skilled in the art will be able to devise various arrangements which, although not explicitly described or shown herein, embody the principles of the invention and are thus within its spirit and scope. 

1. Transparent wrapping paper having high freeness, comprising a paper surface with zigzag embossing in a plan view on the paper surface.
 2. The wrapping paper of claim 1 wherein the zigzag embossing comprises straight connecting distances between apexes in a plan view on the paper surface.
 3. The wrapping paper of claim 1 wherein the zigzag embossing has an apex height substantially perpendicular to a plane defined by paper and wherein the apex height is generally less than 1 mm.
 4. The wrapping paper of claim 1 wherein the transparent wrapping paper exhibits a particular property of slowness of how slowly water is drained from paper pulp that is measured as degrees of Schopper Riegler (SR).
 5. The wrapping paper of claim 4 comprising a freeness of at least 60 SR.
 6. The wrapping paper of claim 1 comprising a basis weight between 40 and 200 g/m².
 7. An envelope material formed from the wrapping paper of claim 1 with high freeness which exhibits a zigzag embossing in a plan view on the paper surface.
 8. A method of manufacturing a transparent wrapping paper comprising embossing a zigzag profile into a transparent paper with high freeness.
 9. A method of manufacturing an envelope comprising the method of claim 8 and further comprising a prior step of folding transparent wrapping paper into an envelope material such that the embossing is performed after folding the paper.
 10. A method of manufacturing an envelope comprising the method of claim 8 and further comprising a subsequent step of folding transparent wrapping paper into an envelope material such that the embossing is performed before folding the paper. 